快速的开发一个完整的iOS直播App(采集)

// 捕获音视频  
- (void)setupCaputureVideo  
{  
    // 1.创建捕获会话,必须要强引用，否则会被释放  
    AVCaptureSession *captureSession = [[AVCaptureSession alloc] init];  
    _captureSession = captureSession;  

    // 2.获取摄像头设备，默认是后置摄像头  
    AVCaptureDevice *videoDevice = [self getVideoDevice:AVCaptureDevicePositionFront];  

    // 3.获取声音设备  
    AVCaptureDevice *audioDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio];  

    // 4.创建对应视频设备输入对象  
    AVCaptureDeviceInput *videoDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:nil];  
    _currentVideoDeviceInput = videoDeviceInput;  

    // 5.创建对应音频设备输入对象  
    AVCaptureDeviceInput *audioDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:audioDevice error:nil];  

    // 6.添加到会话中  
    // 注意“最好要判断是否能添加输入，会话不能添加空的  
    // 6.1 添加视频  
    if ([captureSession canAddInput:videoDeviceInput]) {  
        [captureSession addInput:videoDeviceInput];  
    }  
    // 6.2 添加音频  
    if ([captureSession canAddInput:audioDeviceInput]) {  
        [captureSession addInput:audioDeviceInput];  
    }  

    // 7.获取视频数据输出设备  
    AVCaptureVideoDataOutput *videoOutput = [[AVCaptureVideoDataOutput alloc] init];  
    // 7.1 设置代理，捕获视频样品数据  
    // 注意：队列必须是串行队列，才能获取到数据，而且不能为空  
    dispatch_queue_t videoQueue = dispatch_queue_create("Video Capture Queue", DISPATCH_QUEUE_SERIAL);  
    [videoOutput setSampleBufferDelegate:self queue:videoQueue];  
    if ([captureSession canAddOutput:videoOutput]) {  
        [captureSession addOutput:videoOutput];  
    }  

    // 8.获取音频数据输出设备  
    AVCaptureAudioDataOutput *audioOutput = [[AVCaptureAudioDataOutput alloc] init];  
    // 8.2 设置代理，捕获视频样品数据  
    // 注意：队列必须是串行队列，才能获取到数据，而且不能为空  
    dispatch_queue_t audioQueue = dispatch_queue_create("Audio Capture Queue", DISPATCH_QUEUE_SERIAL);  
    [audioOutput setSampleBufferDelegate:self queue:audioQueue];  
    if ([captureSession canAddOutput:audioOutput]) {  
        [captureSession addOutput:audioOutput];  
    }  

    // 9.获取视频输入与输出连接，用于分辨音视频数据  
    _videoConnection = [videoOutput connectionWithMediaType:AVMediaTypeVideo];  

    // 10.添加视频预览图层  
    AVCaptureVideoPreviewLayer *previedLayer = [AVCaptureVideoPreviewLayer layerWithSession:captureSession];  
    previedLayer.frame = [UIScreen mainScreen].bounds;  
    [self.view.layer insertSublayer:previedLayer atIndex:0];  
    _previedLayer = previedLayer;  

    // 11.启动会话  
    [captureSession startRunning];  
}  

// 指定摄像头方向获取摄像头  
- (AVCaptureDevice *)getVideoDevice:(AVCaptureDevicePosition)position  
{  
    NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];  
    for (AVCaptureDevice *device in devices) {  
        if (device.position == position) {  
            return device;  
        }  
    }  
    return nil;  
}  

#pragma mark - AVCaptureVideoDataOutputSampleBufferDelegate  
// 获取输入设备数据，有可能是音频有可能是视频  
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection  
{  
    if (_videoConnection == connection) {  
        NSLog(@"采集到视频数据");  
    } else {  
        NSLog(@"采集到音频数据");  
    }  
}  

// 切换摄像头  
- (IBAction)toggleCapture:(id)sender {  

    // 获取当前设备方向  
    AVCaptureDevicePosition curPosition = _currentVideoDeviceInput.device.position;  

    // 获取需要改变的方向  
    AVCaptureDevicePosition togglePosition = curPosition == AVCaptureDevicePositionFront?AVCaptureDevicePositionBack:AVCaptureDevicePositionFront;  

    // 获取改变的摄像头设备  
    AVCaptureDevice *toggleDevice = [self getVideoDevice:togglePosition];  

    // 获取改变的摄像头输入设备  
    AVCaptureDeviceInput *toggleDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:toggleDevice error:nil];  

    // 移除之前摄像头输入设备  
    [_captureSession removeInput:_currentVideoDeviceInput];  

    // 添加新的摄像头输入设备  
    [_captureSession addInput:toggleDeviceInput];  

    // 记录当前摄像头输入设备  
    _currentVideoDeviceInput = toggleDeviceInput;  

}  

// 点击屏幕，出现聚焦视图  
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event  
{  
    // 获取点击位置  
    UITouch *touch = [touches anyObject];  
    CGPoint point = [touch locationInView:self.view];  

    // 把当前位置转换为摄像头点上的位置  
    CGPoint cameraPoint = [_previedLayer captureDevicePointOfInterestForPoint:point];  

    // 设置聚焦点光标位置  
    [self setFocusCursorWithPoint:point];  

    // 设置聚焦  
    [self focusWithMode:AVCaptureFocusModeAutoFocus exposureMode:AVCaptureExposureModeAutoExpose atPoint:cameraPoint];  
}  

/**  
 *  设置聚焦光标位置  
 *  
 *  @param point 光标位置  
 */  
-(void)setFocusCursorWithPoint:(CGPoint)point{  
    self.focusCursorImageView.center=point;  
    self.focusCursorImageView.transform=CGAffineTransformMakeScale(1.5, 1.5);  
    self.focusCursorImageView.alpha=1.0;  
    [UIView animateWithDuration:1.0 animations:^{  
        self.focusCursorImageView.transform=CGAffineTransformIdentity;  
    } completion:^(BOOL finished) {  
        self.focusCursorImageView.alpha=0;  

    }];  
}  

/**  
 *  设置聚焦  
 */  
-(void)focusWithMode:(AVCaptureFocusMode)focusMode exposureMode:(AVCaptureExposureMode)exposureMode atPoint:(CGPoint)point{  

    AVCaptureDevice *captureDevice = _currentVideoDeviceInput.device;  
    // 锁定配置  
    [captureDevice lockForConfiguration:nil];  

    // 设置聚焦  
    if ([captureDevice isFocusModeSupported:AVCaptureFocusModeAutoFocus]) {  
        [captureDevice setFocusMode:AVCaptureFocusModeAutoFocus];  
    }  
    if ([captureDevice isFocusPointOfInterestSupported]) {  
        [captureDevice setFocusPointOfInterest:point];  
    }  

    // 设置曝光  
    if ([captureDevice isExposureModeSupported:AVCaptureExposureModeAutoExpose]) {  
        [captureDevice setExposureMode:AVCaptureExposureModeAutoExpose];  
    }  
    if ([captureDevice isExposurePointOfInterestSupported]) {  
        [captureDevice setExposurePointOfInterest:point];  
    }  

    // 解锁配置  
    [captureDevice unlockForConfiguration];  
}